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Home energy storage saves electricity costs? Let's do some calculations together.
Created on 08.06
The ideal is beautiful: the manufacturer's promotion of "freedom of electricity"
Advertising script:
"Install energy storage and save 80% on electricity bills!"
"10 years to break even, earn a battery set for free!"
"Power outage worry-free, self-sufficient!"
Reality:
Energy saving ≠ making money, energy storage is an "electricity cost optimizer," not a "money printing machine."
The payback period is greatly affected by electricity prices, policies, and usage habits.
Calculate a clear account: Taking Shenzhen families as an example
Household Electricity Background:
Monthly electricity consumption: 600 kWh (peak electricity 300 kWh + valley electricity 300 kWh)
Electricity price: Peak electricity ¥1.2/kWh, Valley electricity ¥0.3/kWh
Existing 5kW photovoltaic (self-use during the day, excess electricity connected to the grid at ¥0.45/kWh)
Energy storage solution:
Battery configuration: 10kWh lithium iron phosphate (such as Huawei LUNA2000)
Cost: ¥50,000 (including installation, approximately ¥35,000 after subsidy)
Cycle life: 6000 times (1 charge and discharge per day can be used for 16 years)
Revenue Estimation: Comparison of Three Scenarios
Scene 1: Pure Photovoltaic (No Energy Storage)
Monthly electricity bill:
Use photovoltaic electricity during the day: Free
Evening use of valley electricity: 300 degrees × ¥0.3 = ¥90
Surplus electricity sold: 100 kWh × ¥0.45 = ¥45
Actual expenditure: ¥90 - ¥45 = ¥45
Scenario ② Photovoltaic + Energy Storage (Ideal Model)
Strategy:
During the day, solar power charges the battery (free electricity)
Discharge the battery at night (replace expensive peak electricity)
Monthly electricity bill:
Battery powered: 300 degrees (replacing original peak power)
Still need to purchase electricity: 300 kWh × ¥0.3 = ¥90
Surplus electricity sold: 0 (all for self-use)
Actual expenditure: ¥90 - ¥0 = ¥90
Contradiction: Installing energy storage actually costs an extra ¥45/month!
Scene ③ Photovoltaic + Energy Storage (Optimized Mode)
Strategy:
During the day, prioritize self-use of photovoltaic power, with excess charging the battery.
Low-price charging during off-peak hours (¥0.3/kWh)
Discharge battery during peak electricity period (Save ¥1.2/kWh)
Monthly electricity bill:
Photovoltaic self-use: 200 degrees (free)
Charging for electric vehicles: 100 kWh × ¥0.3 = ¥30
Battery discharge: 300 degrees (save ¥1.2×300=¥360)
Surplus electricity sold: 0
Net Income: ¥360 - ¥30 = ¥330
Payback period: ¥35,000 ÷ (¥330×12) ≈ 8.8 years
The cruel truth: This money cannot be saved
❌ Battery wear: The actual cycle life may only be 4000 times (payback period extended)
❌ Efficiency loss: 10-15% energy loss during charging and discharging
❌ Opportunity cost: ¥35,000 bank deposit annual interest ¥875 (16 years ≈ ¥14,000)
Real return cycle:
Optimistic estimate: 10-12 years
Conservative estimate: Exceeding battery life (blood loss)
What kind of families are suitable for energy storage installation?
✅ High electricity costs: such as Australia (¥2.5/kWh), California (¥1.8/kWh)
✅ Generous subsidies: For example, Germany subsidizes 50%, South Australia subsidizes AU$3000
✅ Frequent power outages: such as in South Africa (average daily power outage of 4 hours)
Situations where installation is not recommended:
Electricity price < ¥0.8/kWh
No photovoltaic support
Cost after subsidy > ¥2.5/kWh
Better alternative solutions
Install photovoltaic first: 5kW system can break even in just 5-6 years
Change in electricity usage habits: Use air conditioning less during peak electricity hours
Buy insurance: Dealing with power outage losses is cheaper than energy storage.
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Summary
The essence of home energy storage is 'electricity price futures'—locking in the electricity price for the next 10 years with today's money. However, if your electricity price is not high enough and the subsidies are not sufficient, it may just be a 'silent investment.'
Suggestion:
First, check the local electricity prices and subsidy policies, and conduct a trial operation of the photovoltaic + valley electricity combination for six months.
Be cautious about the manufacturer's claim of "80% energy saving."
Do you need help calculating a personalized account? Tell me:
City | Monthly Electricity Fee | Is there Photovoltaic
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