Lao Han sells commercial and industrial energy storage cabinets in Suzhou. For his first two years he only worked Jiangsu — plenty of customers, all close by, and whenever he pulled out his payback calculation sheet the numbers looked good. This year he took the same sheet back to the same kind of customers, and once they checked it against their electricity bills, the payback period stretched out noticeably. Several deals that were halfway done stalled on the owner's line: "let me think about it some more." He eventually figured out the problem wasn't the customers — it was the electricity price: last year Jiangsu adjusted the float ratios and time bands for its time-of-use tariff, and the spread narrowed. Selling the same storage cabinet, which province the customer's factory sits in decides whether the math works out.
First, follow the money: the 2026 peak-valley price-spread map
The most basic source of revenue for C&I energy storage is the peak-valley price spread: charge during valley hours, discharge during peak hours. The bigger the spread, the faster the payback. Each province's grid company publishes its agency purchase price every month, and industry bodies use it to rank the spreads. A few key numbers:
- In January 2026, according to the China Energy Storage Alliance (CNESA), the three largest maximum peak-valley spreads were Guangdong's Pearl River Delta five-city zone at 1.1577 yuan/kWh, Jiangmen at 1.1510 yuan/kWh, and Hainan at 1.1171 yuan/kWh. Year-on-year, the maximum spread narrowed in 28 provinces; Jiangsu's fell 45.6% year-on-year, because it had adjusted the float ratios and time bands for its time-of-use tariff a few months earlier.
- In June 2026, based on agency purchase prices compiled by energy-storage industry media, Guangdong's Pearl River Delta five-city zone led at 1.2502 yuan/kWh, and 8 regions had peak-valley spreads above 0.7 yuan/kWh: Guangdong, Tianjin, Hebei, Hunan, Shandong, Chongqing, Zhejiang, and Hainan.
Guangdong's "Pearl River Delta five-city zone" is an electricity-pricing zone designation covering five cities — Guangzhou, Zhuhai, Foshan, Zhongshan, and Dongguan — while Jiangmen, Huizhou, and Shenzhen are each priced separately.
What this map means for sales is direct: for the same storage cabinet, every kWh charged and discharged earns exactly that spread. Between a place with a 1.2-yuan spread and one with a 0.4-yuan spread, the same equipment cycling the same number of times earns three times as much money per day. The visit costs you spend in a low-spread region are unlikely to convert into signed contracts.
Next, find the factories: 74,000 factories in energy-intensive industries
Storage only pays off when installed in factories with heavy power loads. I picked 10 manufacturing industries with high power loads on Tianxia Gongchang: the five manufacturing industries within the National Bureau of Statistics' "six energy-intensive industries" (petroleum and coal processing, chemical raw materials and products, non-metallic mineral products, ferrous metal smelting and rolling, non-ferrous metal smelting and rolling), plus five other high-power-consumption industries — textiles, papermaking, chemical fibers, rubber and plastics, and metal products. Active factories with 50+ insured employees total 73,525; those with 100+ insured employees total 38,316.
Ranked by province:
| Province | Energy-intensive factories with 50+ insured employees | June spread above 0.7 yuan? |
|---|---|---|
| Guangdong | 14,938 | Yes |
| Jiangsu | 10,431 | No |
| Zhejiang | 9,605 | Yes |
| Shandong | 6,000 | Yes |
| Fujian | 2,983 | No |
| Hebei | 2,903 | Yes |
| Hunan | 1,776 | Yes |
| Chongqing | 1,242 | Yes |
| Tianjin | 998 | Yes |
| Hainan | 159 | Yes |
Overlay the two maps and the conclusion falls out: the 8 provinces with a spread above 0.7 yuan together hold 37,621 of these factories — just over half the total. Jiangsu ranks second nationwide by factory count, but in June it wasn't on the list of regions above 0.7 yuan. To sell storage in Jiangsu, the math needs to add in other sources of revenue such as demand management and pairing with solar — the spread alone is a hard sell to the owner.
Guangdong: 8,855 factories in the Pearl River Delta five-city zone — start with Dongguan and Foshan
In the Pearl River Delta five-city zone, which has the highest spread, there are 8,855 energy-intensive factories with 50+ insured employees:
- Dongguan: 4,012
- Foshan: 2,003
- Guangzhou: 1,245
- Zhongshan: 1,147
- Zhuhai: 448
Of the other two separately priced cities that also rank high on spread: Jiangmen has 943 and Huizhou has 1,131.
Broken down by industry, of the 8,855 factories in the Pearl River Delta five-city zone, rubber and plastics account for 3,117 and metal products for 2,919 — together more than half the total. Next are chemicals at 1,021 and non-metallic mineral products at 832. A single factory can belong to two industries at once, so the industry totals add up to slightly more than the overall total.
For storage sales, Dongguan and Foshan are the first cities to work. In Dongguan, rubber and plastics account for 1,773 of these factories and metal products for 1,399; in Foshan, metal products account for 801 and rubber and plastics for 494. High factory count, high spread — schedule factories in the same township or industrial park on the same day, and you can visit several in one day.
Shandong and Zhejiang: one to watch the time-band schedule, one to watch the cities
Shandong: 6,000 energy-intensive factories with 50+ insured employees, concentrated in Qingdao (961), Weifang (768), Yantai (558), Zibo (517), and Jinan (458).
Shandong's time-of-use tariff rules deserve their own look. According to a September report by the Shandong Business Daily, the Shandong Provincial Development and Reform Commission issued a letter (Shandong DRC letter Lu Fagai Jiage Han [2026] No. 68) adjusting the C&I time-of-use tariff time bands effective October 1, 2026, while keeping the float ratios unchanged: peak up 70%, valley down 70%, critical peak up 100%, deep valley down 90%. Compared with the current time bands published by the Weihai Development and Reform Commission in 2025, the changes concentrate on two periods:
- September–November: the valley period moves earlier, from 10:00-15:00 to 9:00-15:00; the peak period extends from 16:00-21:00 to 16:00-22:00; and the critical-peak period extends from 17:00-19:00 to 17:00-20:00.
- March–June (previously March–May and June were run separately): the valley period changes to 8:00-15:00, with 10:00-14:00 as deep valley; the peak period changes to 17:00-23:00, with 17:00-22:00 as critical peak.
The midday valley gets longer and the evening critical peak gets longer; storage charges at midday and discharges in the evening, capturing the spread between deep valley and critical peak. The winter time bands (January-February and December) haven't changed: two valley periods — 2:00-6:00 at night and 10:00-15:00 at midday — and two peak periods — 7:00-9:00 in the morning and 16:00-21:00 in the evening — allow two charge-discharge cycles a day. October is exactly the time to take the new time-band schedule and redo the math.
Zhejiang: 9,605 energy-intensive factories with 50+ insured employees — Ningbo (1,747), Jiaxing (1,442), Hangzhou (1,233), Jinhua (1,164), Taizhou (957), and Shaoxing (889). Each city has its own lead industry: Jiaxing is dominated by textiles (524), Ningbo and Jinhua by metal products (694 and 482), and Taizhou by rubber and plastics (400) — you can switch the industry mix by city and sweep through each area accordingly.
The four things you must ask on the first call
A list can only tell you where a factory is, what it makes, and how many people work there. Whether a storage project can happen also depends on four questions you can ask right there on the phone.
1. How big is the transformer capacity
Industrial users with a contracted capacity of 315 kVA or above generally operate under a two-part tariff: on top of the energy charge billed by consumption, there's a capacity (basic) charge billed by transformer capacity or maximum demand.
For factories billed the capacity charge on a maximum-demand basis, storage can do more than capture the peak-valley spread — it can also discharge during peak demand hours to shave the maximum demand and lower the capacity charge. Ask "what's the transformer capacity at your plant?" — if they can answer, you're talking to someone who understands their electricity bill, and the number they give directly determines how the storage system is sized and how the returns are calculated.
2. Is the electricity bought through grid agency purchase, or on the open market
The spread rankings above are all calculated using the grid company's agency purchase price. If a factory buys electricity through an electricity retailer or participates directly in the power market, its peak-valley prices depend on its own contract. The Basic Rules for the Medium- and Long-Term Electricity Market (Fagai Nengyuangui [2025] No. 1656), issued jointly by the National Development and Reform Commission and the National Energy Administration, specifies that effective March 1, 2026, market entities that trade directly on the market will no longer have artificially set time-of-use price levels and time bands.
So ask this early: for customers on agency purchase, the spread table alone lets you calculate; for customers who buy on the market, ask them for their recent months' electricity bills and calculate off the actual prices.
3. How many shifts, and is the peak period during production
Storage only earns a return by discharging while the factory is actually drawing power. A factory running one daytime shift that shuts down in the evening can't use the evening peak period; a factory running two or three shifts continuously always has load during the peak period, so the discharged power actually gets used. Ask "how many shifts do you run, and what time do you shut down at night?" and you can tell whether the factory fits.
4. Is there space for it, and is the building owned or leased
Storage cabinets need floor space and have to meet fire-safety clearance requirements. Whether the plant has open space, whether the building is owned or leased, and how many years are left on the lease all determine whether the project can actually be built and how long a contract can run. For leased buildings, the landlord usually has to sign off too.
Once you've asked all four questions, the factories on your list split into three groups: ready for a proposal right away, needing more information before you can calculate, and not a fit for now.
A sequence you can run right away
- Narrow to provinces first: from the 8 provinces where the June spread exceeded 0.7 yuan, pick the range your company can actually deliver and service.
- Then narrow to industry and size: on Tianxia Gongchang, filter by energy-intensive industry plus insured headcount — start with 100+ insured employees, then expand down to 50+. For example, in the Pearl River Delta five-city zone, there are 4,400 factories with 100+ insured employees, which you can filter directly with this list; widening to 50+ gives 8,855, matching this list.
- Route by city: schedule factories in the same industrial park on the same day — in cities like Dongguan, Foshan, Ningbo, and Jiaxing, seeing four or five factories in a day is a normal pace.
- Ask only the four things on the first call: transformer capacity, how power is purchased, shift schedule, and site. Decide whether to visit in person only after you've asked all four.
- Build the proposal off the electricity bill: calculate agency-purchase customers off the spread table, market-purchase customers off their settlement statements, and calculate the demand charge separately.
You can also just ask the AI on Tianxia Gongchang something like "Foshan metal-products and plastic-products factories with 100+ insured employees", and it will break the criteria down into filters and list the factories.
After storage, the next stop is the rooftop
Salespeople working storage will find that out of every ten factories, a few owners turn the question around: "would it be worth putting solar on the roof?" Storage depends on the spread and the load; solar depends on the roof and daytime power use — the customer profiles overlap, but they're also clearly different. For how to find rooftop solar factory customers, see the next article in this series: How to Find Factory Customers for Commercial Rooftop Solar Sales.
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Published by the Tianxia Gongchang Research Institute. Data notes: factory counts are from Tianxia Gongchang, covering active manufacturing factories with 50+ insured employees, as of September 2026; peak-valley spreads are from the China Energy Storage Alliance's January 2026 statistics and energy-storage industry media's compilation of grid-company agency purchase prices for June 2026; Shandong's time-of-use tariff rules are from the Weihai Development and Reform Commission's policy interpretation (April 2025) and a Shandong Business Daily report (September 2026); the "six energy-intensive industries" definition is from the National Bureau of Statistics.