![\"PEAK\"](\"https:\/\/hdxenergy.com\/wp-content\/uploads\/2026\/02\/PEAK-1024x683.jpg\")
<\/figure>\n\n\n\n\n\n\n\n
The three numbers you need before you estimate savings<\/h2>\n\n\n\n
You don\u2019t need a spreadsheet to get started, but you do need three facts you can confirm in about 15 minutes.<\/p>\n\n\n\n
1) Your utility\u2019s TOU plan and peak\/off\u2011peak hours<\/h3>\n\n\n\n\n- PG&E: Peak is 4\u20139 p.m. daily on E\u2011TOU\u2011C. See the official plan document in the PG&E E\u2011TOU\u2011C tariff PDF for precise hours and current charges. Source: the PG&E schedule in the E\u2011TOU\u2011C tariff PDF<\/strong><\/a>.<\/li>\n\n\n\n
- SCE: Residential TOU\u2011D options commonly use 4\u20139 p.m. or 5\u20138 p.m. peaks depending on the option and season. Confirm the exact hours for your active option via SCE\u2019s rate pages and current tariff PDFs. Start with the SCE residential TOU plan overview<\/strong><\/a>.<\/li>\n\n\n\n
- SDG&E: Many plans (e.g., TOU\u2011DR1) include On\u2011Peak 4\u20139 p.m., plus Off\u2011Peak and Super Off\u2011Peak periods. Verify the latest hours and seasons on the SDG&E \u201cWhen Matters\u201d page<\/strong><\/a> and the live tariff PDF for your plan.<\/li>\n<\/ul>\n\n\n\n
Tip: Don\u2019t rely on screenshots\u2014TOU windows can change. Always open the current PDF for your exact plan.<\/p>\n\n\n\n
2) How export credits work under NEM 3.0<\/h3>\n\n\n\n
Under NEM 3.0, your exported solar earns hourly credits derived from the CPUC\u2019s Avoided Cost Calculator (ACC). Midday credits are often lower; evening credits can be higher. The mechanics are described in the CPUC\u2019s documentation; see the 2024 ACC documentation<\/strong><\/a> and the CPUC DER cost\u2011effectiveness hub<\/strong><\/a>. For estimating, you only need to recognize that value varies by hour and season.<\/p>\n\n\n\n3) Your household\u2019s evening usage (kWh) during peak<\/h3>\n\n\n\n
Look up your smart\u2011meter interval data or monthly usage chart to estimate how many kilowatt\u2011hours you typically use in peak windows (often 4\u20139 p.m.). If you don\u2019t have exact interval data, a rough estimate is fine for a first pass; you\u2019ll refine it with your installer.<\/p>\n\n\n\n
\n\n\n\nHow home battery TOU arbitrage in California works under NEM 3.0<\/h2>\n\n\n\n
Think of your battery as a time machine for electricity. You \u201cstore\u201d energy when prices (and export credits) are low and \u201cspend\u201d it when prices (or export credits) are higher. Under NEM 3.0, this often means charging from midday solar or off\u2011peak grid hours and discharging from 4\u20139 p.m.<\/p>\n\n\n\n![\"TOU](\"https:\/\/hdxenergy.com\/wp-content\/uploads\/2026\/02\/TOU-price-bands-1024x683.jpg\")
<\/figure>\n\n\n\nWhat changes the math under NEM 3.0 is that export credits no longer match retail import prices. They\u2019re set hourly using the ACC, which means midday exports are usually worth less than evening energy. By discharging during peak hours, you avoid high\u2011priced imports and may direct your solar to higher\u2011value hours rather than exporting it at midday.<\/p>\n\n\n\n
\n\n\n\nA simple way to estimate savings (beginner\u2011friendly)<\/h2>\n\n\n\n
We\u2019ll keep it conservative and simple. You\u2019ll plug in a few numbers you gathered above and do quick math.<\/p>\n\n\n\n
Assumptions to set with your installer later: usable battery capacity (kWh), round\u2011trip efficiency (~90\u201395%), your TOU peak\/off\u2011peak price difference, and a sense of export credit patterns for your utility.<\/p>\n\n\n\n
Back\u2011of\u2011envelope formula (daily):<\/p>\n\n\n\n
Daily arbitrage value \u2248 (kWh discharged during peak \u00d7 retail peak price) \n \u2212 (kWh charged from grid \u00d7 off-peak price) \n + (kWh shifted from low-credit hours to high-value hours \u00d7 credit uplift)\n<\/code><\/pre>\n\n\n\nWorked example (illustrative only):<\/p>\n\n\n\n
\n- Suppose you have a ~10 kWh usable battery and target covering 8 kWh of your 4\u20139 p.m. usage. If your off\u2011peak price is materially lower than peak, and midday export credits are typically lower than evening value, your battery can avoid several kWh of expensive imports during peak and shift solar from low\u2011credit midday to higher\u2011value evening hours. Because exact cents\/kWh and export credits change, confirm numbers in your utility\u2019s live tariff PDFs and ACC\u2011based references before relying on any estimate.<\/li>\n<\/ul>\n\n\n\n
This simple savings frame is the core of home battery TOU arbitrage in California: charge low, discharge high, and increase self\u2011consumption when midday export credits are relatively low.<\/p>\n\n\n\n
\n\n\n\nCalifornia micro\u2011case studies (illustrative)<\/h2>\n\n\n\n
These sketches use 4\u20139 p.m. peaks where applicable and keep numbers qualitative to avoid quoting stale cents\/kWh. Check the linked official pages for current values.<\/p>\n\n\n\n
PG&E (E\u2011TOU\u2011C)<\/h3>\n\n\n\n
On PG&E\u2019s E\u2011TOU\u2011C, peak runs 4\u20139 p.m. daily. If your evening usage is, say, 6\u201310 kWh, a 10\u201313.5 kWh battery can be scheduled to discharge through most of that peak window. The value comes from avoiding imports at peak retail prices and reserving some midday solar in the battery rather than exporting it for lower midday credits. See PG&E\u2019s official E\u2011TOU\u2011C tariff PDF<\/strong><\/a> for hours and rate components.<\/p>\n\n\n\nSCE (TOU\u2011D variants)<\/h3>\n\n\n\n
SCE offers TOU\u2011D options commonly centered on 4\u20139 p.m. or 5\u20138 p.m. peaks (some options vary by season or weekday). A homeowner targeting 5\u20138 kWh of evening usage could schedule discharge to overlap the full peak window. Verify your exact TOU\u2011D option and hours on the SCE residential TOU overview<\/strong><\/a>, then pull the live tariff PDF before calculating.<\/p>\n\n\n\nSDG&E (TOU\u2011DR family)<\/h3>\n\n\n\n
Many SDG&E plans include On\u2011Peak 4\u20139 p.m., with Off\u2011Peak and Super Off\u2011Peak periods. Batteries can charge from midday solar or super off\u2011peak and discharge through the 4\u20139 p.m. peak to avoid high retail prices while making better use of your own solar. Confirm your plan\u2019s current hours and seasons via SDG&E\u2019s When Matters page<\/strong><\/a> and the associated tariff PDF.<\/p>\n\n\n\nA neutral micro\u2011example using HDX Energy<\/h3>\n\n\n\n
Disclosure: HDX Energy is our product.<\/p>\n\n\n\n
A first\u2011time homeowner with a 10 kWh LiFePO4 home battery wants to cover most of the 4\u20139 p.m. window. They schedule \u201ccharge preference\u201d for midday solar and allow supplemental off\u2011peak charging if the battery isn\u2019t full by late afternoon. The evening discharge target is set to hold a minimum reserve for overnight needs. This approach reduces peak imports and increases the value of self\u2011consumed solar under NEM 3.0.<\/p>\n\n\n\n
\n\n\n\nRight\u2011sizing the battery and day\u2011to\u2011day operation<\/h2>\n\n\n\n
Size to your evening usage first, then consider backup goals. If you typically use 6\u20138 kWh between 4 and 9 p.m., a 10\u201313.5 kWh battery often covers that window with some margin for reserves, round\u2011trip losses, and partial winter solar. If whole\u2011home backup is also important, you may size up or configure critical\u2011load circuits to stretch runtime.<\/p>\n\n\n\n
Operationally, most homeowners set: (1) a charging preference for midday solar or off\u2011peak; (2) a discharge window aligned with peak; and (3) a reserve percentage to keep some energy for late\u2011night or backup. Efficiency, depth\u2011of\u2011discharge limits, and inverter power (kW) all affect how far and how fast the battery can carry your home during peak\u2014your installer will match settings to your priorities.<\/p>\n\n\n\n
\n\n\n\nInstaller checklist (use this to get apples\u2011to\u2011apples quotes)<\/h2>\n\n\n\n\n- Your IOU and current TOU plan name, with a link to the live tariff PDF<\/li>\n\n\n\n
- Estimated evening kWh during peak (e.g., 4\u20139 p.m.) from smart\u2011meter data<\/li>\n\n\n\n
- Desired coverage: critical loads vs. whole\u2011home during peak and for backup<\/li>\n\n\n\n
- Target battery size (kWh usable) and any preferred reserve percentage<\/li>\n\n\n\n
- Confirmation that the system\/inverter meets UL 9540\/1973\/1741 and local AHJ requirements<\/li>\n\n\n\n
- NEM 3.0 export\u2011credit assumptions the installer uses and how schedules are set<\/li>\n\n\n\n
- SGIP status: whether you may qualify for Residential Storage & Solar Equity and how to apply via SelfGenCA<\/li>\n<\/ul>\n\n\n\n
For SGIP updates and budget availability, check the official portal\u2019s announcements on SelfGenCA<\/strong><\/a> and, for the 2025 program expansion context, see the CPUC\u2019s news release announcing $280 million for the Residential Storage & Solar Equity program (2025)<\/strong><\/a>. Program rules and budgets can change; always verify the latest status.<\/p>\n\n\n\n
\n\n\n\nSafety and certifications (what permits and insurers expect)<\/h2>\n\n\n\n
California jurisdictions generally look for UL\u2011listed systems and code\u2011compliant placements. Residential systems are typically listed to UL 9540 at the system level, with batteries evaluated under UL 1973 and inverters to UL 1741; UL 9540A testing is often referenced for fire\u2011safety and spacing considerations in NFPA 855 and building codes. For background, see UL\u2019s overview of energy storage system testing and certification<\/strong><\/a> and state workshop materials hosted by energy agencies.<\/p>\n\n\n\nMany homeowners also ask about chemistry: modern LiFePO4 batteries are known for stable thermal behavior and long cycle life when properly engineered and certified. Regardless of brand, verify listings, installation clearances, and local permitting notes with your installer and Authority Having Jurisdiction (AHJ).<\/p>\n\n\n\n
\n\n\n\nResources and next steps<\/h2>\n\n\n\n\n- CPUC sources on export credits and the ACC: DER cost\u2011effectiveness hub<\/strong><\/a> and the 2024 ACC documentation<\/strong><\/a><\/li>\n\n\n\n
- Utility TOU periods and tariffs: PG&E E\u2011TOU\u2011C tariff PDF<\/strong><\/a>; SCE residential TOU overview<\/strong><\/a>; SDG&E When Matters (TOU) page<\/strong><\/a><\/li>\n<\/ul>\n\n\n\n
Want help configuring time\u2011based control for arbitrage? See our brief walkthrough on HDX Energy.<\/p>\n\n\n\n
\n\n\n\nSmall\u2011print notes<\/p>\n\n\n\n
\n- Policies and prices change. Always rely on your live tariff PDFs and current ACC\u2011based export credit references.<\/li>\n\n\n\n
- This guide is informational and not financial advice; consult your utility, installer, and local permitting authority for specifics.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"
If you own solar in California or you\u2019re planning to, you\u2019ve probably heard that NEM 3.0 (the Net Billing Tariff) lowered midday export credits. That change makes a home battery useful not just for backup, but for shifting energy from low\u2011value hours to high\u2011value hours\u2014also known as Time\u2011of\u2011Use (TOU) arbitrage. This beginner\u2019s guide shows you […]<\/p>\n","protected":false},"author":1,"featured_media":1356,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1355","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/comments?post=1355"}],"version-history":[{"count":1,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355\/revisions"}],"predecessor-version":[{"id":1358,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355\/revisions\/1358"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/media\/1356"}],"wp:attachment":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/media?parent=1355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/categories?post=1355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/tags?post=1355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Tip: Don\u2019t rely on screenshots\u2014TOU windows can change. Always open the current PDF for your exact plan.<\/p>\n\n\n\n
2) How export credits work under NEM 3.0<\/h3>\n\n\n\n
Under NEM 3.0, your exported solar earns hourly credits derived from the CPUC\u2019s Avoided Cost Calculator (ACC). Midday credits are often lower; evening credits can be higher. The mechanics are described in the CPUC\u2019s documentation; see the 2024 ACC documentation<\/strong><\/a> and the CPUC DER cost\u2011effectiveness hub<\/strong><\/a>. For estimating, you only need to recognize that value varies by hour and season.<\/p>\n\n\n\n Look up your smart\u2011meter interval data or monthly usage chart to estimate how many kilowatt\u2011hours you typically use in peak windows (often 4\u20139 p.m.). If you don\u2019t have exact interval data, a rough estimate is fine for a first pass; you\u2019ll refine it with your installer.<\/p>\n\n\n\n Think of your battery as a time machine for electricity. You \u201cstore\u201d energy when prices (and export credits) are low and \u201cspend\u201d it when prices (or export credits) are higher. Under NEM 3.0, this often means charging from midday solar or off\u2011peak grid hours and discharging from 4\u20139 p.m.<\/p>\n\n\n\n What changes the math under NEM 3.0 is that export credits no longer match retail import prices. They\u2019re set hourly using the ACC, which means midday exports are usually worth less than evening energy. By discharging during peak hours, you avoid high\u2011priced imports and may direct your solar to higher\u2011value hours rather than exporting it at midday.<\/p>\n\n\n\n We\u2019ll keep it conservative and simple. You\u2019ll plug in a few numbers you gathered above and do quick math.<\/p>\n\n\n\n Assumptions to set with your installer later: usable battery capacity (kWh), round\u2011trip efficiency (~90\u201395%), your TOU peak\/off\u2011peak price difference, and a sense of export credit patterns for your utility.<\/p>\n\n\n\n Back\u2011of\u2011envelope formula (daily):<\/p>\n\n\n\n Worked example (illustrative only):<\/p>\n\n\n\n This simple savings frame is the core of home battery TOU arbitrage in California: charge low, discharge high, and increase self\u2011consumption when midday export credits are relatively low.<\/p>\n\n\n\n These sketches use 4\u20139 p.m. peaks where applicable and keep numbers qualitative to avoid quoting stale cents\/kWh. Check the linked official pages for current values.<\/p>\n\n\n\n On PG&E\u2019s E\u2011TOU\u2011C, peak runs 4\u20139 p.m. daily. If your evening usage is, say, 6\u201310 kWh, a 10\u201313.5 kWh battery can be scheduled to discharge through most of that peak window. The value comes from avoiding imports at peak retail prices and reserving some midday solar in the battery rather than exporting it for lower midday credits. See PG&E\u2019s official E\u2011TOU\u2011C tariff PDF<\/strong><\/a> for hours and rate components.<\/p>\n\n\n\n SCE offers TOU\u2011D options commonly centered on 4\u20139 p.m. or 5\u20138 p.m. peaks (some options vary by season or weekday). A homeowner targeting 5\u20138 kWh of evening usage could schedule discharge to overlap the full peak window. Verify your exact TOU\u2011D option and hours on the SCE residential TOU overview<\/strong><\/a>, then pull the live tariff PDF before calculating.<\/p>\n\n\n\n Many SDG&E plans include On\u2011Peak 4\u20139 p.m., with Off\u2011Peak and Super Off\u2011Peak periods. Batteries can charge from midday solar or super off\u2011peak and discharge through the 4\u20139 p.m. peak to avoid high retail prices while making better use of your own solar. Confirm your plan\u2019s current hours and seasons via SDG&E\u2019s When Matters page<\/strong><\/a> and the associated tariff PDF.<\/p>\n\n\n\n Disclosure: HDX Energy is our product.<\/p>\n\n\n\n A first\u2011time homeowner with a 10 kWh LiFePO4 home battery wants to cover most of the 4\u20139 p.m. window. They schedule \u201ccharge preference\u201d for midday solar and allow supplemental off\u2011peak charging if the battery isn\u2019t full by late afternoon. The evening discharge target is set to hold a minimum reserve for overnight needs. This approach reduces peak imports and increases the value of self\u2011consumed solar under NEM 3.0.<\/p>\n\n\n\n Size to your evening usage first, then consider backup goals. If you typically use 6\u20138 kWh between 4 and 9 p.m., a 10\u201313.5 kWh battery often covers that window with some margin for reserves, round\u2011trip losses, and partial winter solar. If whole\u2011home backup is also important, you may size up or configure critical\u2011load circuits to stretch runtime.<\/p>\n\n\n\n Operationally, most homeowners set: (1) a charging preference for midday solar or off\u2011peak; (2) a discharge window aligned with peak; and (3) a reserve percentage to keep some energy for late\u2011night or backup. Efficiency, depth\u2011of\u2011discharge limits, and inverter power (kW) all affect how far and how fast the battery can carry your home during peak\u2014your installer will match settings to your priorities.<\/p>\n\n\n\n For SGIP updates and budget availability, check the official portal\u2019s announcements on SelfGenCA<\/strong><\/a> and, for the 2025 program expansion context, see the CPUC\u2019s news release announcing $280 million for the Residential Storage & Solar Equity program (2025)<\/strong><\/a>. Program rules and budgets can change; always verify the latest status.<\/p>\n\n\n\n California jurisdictions generally look for UL\u2011listed systems and code\u2011compliant placements. Residential systems are typically listed to UL 9540 at the system level, with batteries evaluated under UL 1973 and inverters to UL 1741; UL 9540A testing is often referenced for fire\u2011safety and spacing considerations in NFPA 855 and building codes. For background, see UL\u2019s overview of energy storage system testing and certification<\/strong><\/a> and state workshop materials hosted by energy agencies.<\/p>\n\n\n\n Many homeowners also ask about chemistry: modern LiFePO4 batteries are known for stable thermal behavior and long cycle life when properly engineered and certified. Regardless of brand, verify listings, installation clearances, and local permitting notes with your installer and Authority Having Jurisdiction (AHJ).<\/p>\n\n\n\n Want help configuring time\u2011based control for arbitrage? See our brief walkthrough on HDX Energy.<\/p>\n\n\n\n Small\u2011print notes<\/p>\n\n\n\n If you own solar in California or you\u2019re planning to, you\u2019ve probably heard that NEM 3.0 (the Net Billing Tariff) lowered midday export credits. That change makes a home battery useful not just for backup, but for shifting energy from low\u2011value hours to high\u2011value hours\u2014also known as Time\u2011of\u2011Use (TOU) arbitrage. This beginner\u2019s guide shows you […]<\/p>\n","protected":false},"author":1,"featured_media":1356,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1355","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/comments?post=1355"}],"version-history":[{"count":1,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355\/revisions"}],"predecessor-version":[{"id":1358,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/posts\/1355\/revisions\/1358"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/media\/1356"}],"wp:attachment":[{"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/media?parent=1355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/categories?post=1355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hdxenergy.com\/en\/wp-json\/wp\/v2\/tags?post=1355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}3) Your household\u2019s evening usage (kWh) during peak<\/h3>\n\n\n\n
\n\n\n\nHow home battery TOU arbitrage in California works under NEM 3.0<\/h2>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nA simple way to estimate savings (beginner\u2011friendly)<\/h2>\n\n\n\n
Daily arbitrage value \u2248 (kWh discharged during peak \u00d7 retail peak price) \n \u2212 (kWh charged from grid \u00d7 off-peak price) \n + (kWh shifted from low-credit hours to high-value hours \u00d7 credit uplift)\n<\/code><\/pre>\n\n\n\n\n
\n\n\n\nCalifornia micro\u2011case studies (illustrative)<\/h2>\n\n\n\n
PG&E (E\u2011TOU\u2011C)<\/h3>\n\n\n\n
SCE (TOU\u2011D variants)<\/h3>\n\n\n\n
SDG&E (TOU\u2011DR family)<\/h3>\n\n\n\n
A neutral micro\u2011example using HDX Energy<\/h3>\n\n\n\n
\n\n\n\nRight\u2011sizing the battery and day\u2011to\u2011day operation<\/h2>\n\n\n\n
\n\n\n\nInstaller checklist (use this to get apples\u2011to\u2011apples quotes)<\/h2>\n\n\n\n
\n
\n\n\n\nSafety and certifications (what permits and insurers expect)<\/h2>\n\n\n\n
\n\n\n\nResources and next steps<\/h2>\n\n\n\n
\n
\n\n\n\n\n