Xiao Lin has been developing commercial and industrial (C&I) rooftop solar for three years, and his way of finding customers has always been driving around to look at rooftops, or circling big blue color-steel roofs on satellite maps. Once he found a roof, he'd report it to the investor, and the reasons it got sent back kept converging on the same few things: "daytime power consumption isn't enough, the self-consumption ratio doesn't pencil out," "the building is rented and the landlord won't sign," "the company has only been around for three years, but the contract runs twenty, and risk control won't approve it." He later switched the order: screen the factory first, then look at the roof.
The Rules Have Changed: Rooftop Power Has to Be Self-Consumed First
In January 2025, the National Energy Administration (NEA) issued the Administrative Measures for the Development and Construction of Distributed PV (NEA document Guonengfa Xinnenggui [2025] No. 7), dividing distributed PV into four categories: residential (natural-person) household use, non-natural-person household use, general commercial and industrial (C&I), and large C&I. The two categories relevant to factory rooftops are the latter two:
- General C&I: built on commercial and industrial factory buildings and their auxiliary sites, with a grid connection voltage no higher than 10 kV (20 kV) and total installed capacity in principle no more than 6 MW. The grid mode is a choice between full self-consumption and self-consumption with surplus exported to the grid.
- Large C&I: grid connection voltage of 35 kV with total installed capacity in principle no more than 20 MW, or voltage of 110 kV (66 kV) with total installed capacity in principle no more than 50 MW. In principle, full self-consumption is required; in regions where the electricity spot market runs continuously, self-consumption with surplus exported to the grid is allowed to participate in the spot market.
That same year, "Document No. 136" (Fagai Jiage [2025] No. 136) from the National Development and Reform Commission (NDRC) and the NEA drew a line at June 1, 2025: for new renewable-energy capacity commissioned after that date, the volume of electricity brought under the pricing mechanism is set by each region, and the mechanism price is formed through annual voluntary bidding organized by each region.
Put the two documents together, and the implication for sales is clear: power generated by rooftop solar on a factory has to be mostly consumed by the factory itself. No matter how big the roof is, if the power can't be used up during the day, the numbers on the project won't work. The first screening criterion for finding customers has shifted from "roof area" to "daytime power consumption."
Three Things Investors Look At: Power Use, the Roof, and Whether This Factory Will Still Be Around in 20 Years
C&I rooftop solar widely uses the energy performance contracting (EMC) model: the investor funds and builds the power station, and the factory buys electricity at a discounted rate. According to law firms' reviews of this type of contract, the cooperation period is typically set at 20 years, with a 5-year renewal after expiry, or a 20-year contract and a 5-year contract signed at the same time; the electricity price is usually a discount off the grid's tax-inclusive industrial electricity price.
Once you sign, it's twenty or thirty years, so besides power use and the roof, there's one more thing investors care most about: whether this factory might shut down or relocate partway through. You have to visit in person to check the roof, and check the electricity bills to see power use, but "how stable is this factory" is something you can screen for before you even make the call. Tianxia Gongchang has three signals you can use directly:
- Insured headcount: factories with more insured employees usually also have larger power consumption and production scale.
- Years in business: factories that have operated for more than ten years have weathered several industry cycles.
- Registered capital: factories with deeper capital reserves have a stronger cushion against industry swings.
I used these three signals to build a filter; I set the thresholds myself, and you can adjust them to match your investment partner's risk-control requirements:
| Filter criteria | Active manufacturing factories |
|---|---|
| 50+ insured employees | 171,426 |
| + in business 10+ years | 134,336 |
| + registered capital above 10 million yuan | 98,092 |
If you relax registered capital to above 5 million yuan, that's 113,869 factories; if you relax insured headcount to 20+, that's 155,520 factories.
98,092 factories are the first prospect list for rooftop solar sales: large enough in scale, long enough in business, and deep enough in capital. Whether the roof itself is suitable is something to confirm factory by factory in the next step.
Where Are These 98,000 Factories
By province:
| Province | Factories |
|---|---|
| Guangdong | 15,709 |
| Jiangsu | 15,228 |
| Zhejiang | 13,308 |
| Shandong | 7,945 |
| Fujian | 3,897 |
| Sichuan | 3,767 |
| Hebei | 3,630 |
| Anhui | 3,491 |
| Shanghai | 3,224 |
| Henan | 3,050 |
By city, the top ten are Suzhou with 4,517 factories, Dongguan with 3,444 factories, Shenzhen with 3,212 factories, Shanghai with 3,185 factories, Wuxi with 2,454 factories, Hangzhou with 2,142 factories, Ningbo with 2,120 factories, Wenzhou with 1,911 factories, Chengdu with 1,910 factories, and Guangzhou with 1,852 factories.
Big cities like Shenzhen and Shanghai rank near the top, but when working rooftop solar in big cities, confirm first whether the building is single-story or multi-story and whether it's owned or leased, before you even discuss the roof. Manufacturing cities like Suzhou, Dongguan, Wuxi, and Ningbo have a high density of factories on the list and are well suited to working whole industrial zones at once — a good choice for your first batch.
By industry, the largest categories among these 98,000 factories are general equipment with 12,888 factories, special-purpose equipment with 11,320 factories, metal products with 10,448 factories, computer, communication, and electronic equipment with 9,714 factories, electrical machinery and equipment with 8,721 factories, non-metallic mineral products with 8,619 factories, chemical raw materials and chemical products with 8,142 factories, rubber and plastics with 7,294 factories, and automobiles with 7,221 factories (a factory may fall under two industries at once).
One Detail Worth Getting Right: Electricity Prices May Be in the Valley Period Exactly When Solar Is Generating
Solar generates the most power around midday. But to absorb solar output, some provinces have already set midday as a valley period, or even a deep valley. Take Shandong: according to Shandong Commercial Daily's coverage of a document issued by the Shandong Provincial Development and Reform Commission (Shandong DRC letter Lu Fagai Jiage Han [2026] No. 68), under the time-of-use schedule effective October 1, 2026, midday falls in the valley period year-round except in July and August: 10:00-15:00 in January-February and December, 8:00-15:00 in March-June, and 9:00-15:00 in September-November, with 10:00-14:00 in the March-June window and 11:00-14:00 in the other two windows classified as deep valley. The same document sets the valley-period price at a 70% discount and the deep-valley price at a 90% discount.
That means in provinces like Shandong, solar is displacing power that was already cheap valley-period electricity, and if the EMC discount is applied to the average price, the factory will very likely find it doesn't pencil out once it runs the numbers by time-of-use period. When pitching rooftop solar in these provinces, either calculate returns by time-of-use period, or pitch it together with energy storage: solar charges at midday, storage discharges at the evening peak. For how to find factory customers for commercial and industrial energy storage, see the previous article in this series: How to Find Factory Customers for Commercial and Industrial Energy Storage Sales.
Five Things to Nail Down in the First Phone Call
- Is the building owned or rented: for an owned building, the rooftop contract is signed with the factory; for a rented building, the roof's owner is the landlord, so the contract needs the landlord's signature, and you also need to check how many years are left on the lease.
- What's the roof structure, and how old is it: color-steel or concrete — whether a color-steel roof's remaining service life can cover the contract term determines whether the roof needs to be renovated first.
- How much power is used during the day: ask for the last 12 months of electricity bills and look at daytime power consumption — this is the foundation for the self-consumption ratio.
- Does production stop on weekends and holidays: on days when production stops, the power solar generates can't be used and can only be exported to the grid or wasted. The more days of the year production stops, the lower the self-consumption ratio.
- What voltage level is the grid connection: 10 kV or above 35 kV determines whether the project is managed as general C&I or large C&I, and also determines which grid mode can be chosen.
Of these five questions, the first and fourth are the best ones to ask on the phone, and the ones that most quickly screen out unsuitable factories.
A Sequence You Can Run Right Away
- Generate the list first: on Tianxia Gongchang, filter by "50+ insured employees + in business 10+ years + registered capital above 10 million yuan" — for example, general equipment, special-purpose equipment, and metal-products factories in Suzhou can be filtered directly with this list.
- Then check the roof: use satellite maps to check each factory's roof area and structure one by one, and rule out any with obviously too-small roofs or multi-story buildings first.
- Ask only two things on the call: whether the building is owned, and whether production stops on weekends and holidays. If both answers work, schedule a site visit.
- Get the electricity bills on-site: calculate the self-consumption ratio and returns by time-of-use period, and for provinces where midday is a valley period, also present an energy-storage pairing option.
- Bring the numbers when you meet the owner: under the EMC model the factory doesn't pay anything upfront, so what the owner cares about is what discount the electricity price gets, whether the roof will leak, and who owns the power station once the contract ends — have answers to these three questions ready in advance.
You can also just ask Tianxia Gongchang's AI directly, something like "Dongguan hardware and machinery factories in business 10+ years with 100+ insured employees," and it will break the conditions into filters and list out the factories.
Of the rooftop list you have on hand right now, how many were circled by roof area before the rules changed? Run it back through the five questions above — whatever survives is the customer actually worth pursuing this round.
→ Filter Tianxia Gongchang for factories in business 10+ years, with 50+ insured employees, and registered capital above 10 million yuan | → Get a Tianxia Gongchang membership
Published by the Tianxia Gongchang Research Institute. Data notes: factory counts are from Tianxia Gongchang, covering active-status manufacturing factories as of September 2026; policy provisions are from the National Energy Administration's Administrative Measures for the Development and Construction of Distributed PV and its policy interpretation (January 2025), and "Document No. 136" from the National Development and Reform Commission and the National Energy Administration; the EMC contract term is from publicly available law firm articles; Shandong's time-of-use electricity prices are from the Weihai Development and Reform Commission's policy interpretation (April 2025) and Shandong Commercial Daily's report (September 2026).