The ZERO Electricity Bill Dilemma

Last month, I had shared the details of my family’s six-month-old home solar PV journey in Shah Alam, Malaysia. The data is amazing, and I want to share this good news with the Malaysian public. Our experience proves that with strategic sizing and current market prices, solar is a really good investment.

Before our installation, our family faced monthly TNB electricity bills of approximately MYR 960. As high-consumption users, we were trapped in the most expensive tariff blocks. By utilizing the NEM (Net Energy Metering) Rakyat program, we aimed for a total offset.

To put the current market into perspective, consider how far we have come. Twenty years ago, residential solar in Malaysia was a pioneering luxury, costing over RM 26,000 per kWp[1]. Today, the technology has matured and scaled so rapidly that we opted for a large 17.98 kWp system at a total cost of MYR 36,050. That works out to just RM 2,016 per kWp, a 92% price reduction over two decades.

Figure 1: Our 17.98 kWp solar roof installation

The Financial Breakdown

The table shows the key economic figures concerning our residential solar installation in mid-2025

METRIC	VALUE	IMPACT
System Size	17.98 kWp
TNB Bill (Before)	MYR 960	High tariff block exposure
TNB Bill (Now)	MYR 0	Fully offset by NEM credits
Final Investment	RM 36,050	~RM 2,000 per kWp
Payback Period	3.1 Years
Return on Investment	31%

Figure 2: TNB Electric bill BEFORE Solar installation

Figure 3: TNB Electric bill AFTER Solar installation

As of 31st December 2025, our system generated an excess of ~1,500 kWh beyond our consumption. Under current rules, this energy is banked at the TNB grid. However, on 1st January 2026, this balance resets to zero. This "use it or lose it" rule is the first hint that the grid cannot indefinitely act as a free battery for everyone.

The Looming Crisis: Malaysia’s Future "Duck Curve"

While my family is currently reaping the benefits, a big shift might be coming. Because solar prices have dropped so drastically, adoption is exploding. This will inevitably lead us to a technical tipping point known as The Duck Curve.

Figure 4: Solar Power Duck Curve

This happens when a massive surge of solar floods the grid around noon, causing net demand to crash (the belly of the duck), followed by a sharp spike in grid demand when the sun sets (the neck of the duck).

Lessons from Europe

Malaysia hasn't hit a critical Duck Curve yet, but we might be following the path of European countries that have implemented dynamic hour-by-hour electricity pricing. Data from ElectricityMaps.com highlights the challenges we will soon face:

1) The Energy Mix Gap: The biggest difference lies in the energy mix (Figures 5 & 6). In Denmark, coal has been largely phased out in favor of wind, solar, and hydro, allowing them to hit near 100% renewable utilization on high-wind days. Malaysia, however, remains highly dependent on coal and gas for over 80% of its power. This creates a technical bottleneck. Unlike Denmark's flexible green grid, our "always-on" coal plants cannot be easily or cheaply switched off for just a few hours when the sun is at its peak. This makes the surge of solar at noon a potential liability for our grid stability, creating a Duck Curve that is much harder to manage than in countries that have already moved away from heavy fossil fuels.

Figure 5: Malaysia's Electricity Mix, mostly from fossil fuel

Figure 6: Denmark's Electricity Mix, high fraction of renewables

2) The Risk of Overproduction: In Denmark, daytime solar and wind production is sometimes so high that the supply graph dips below zero. This means they are producing more than they can consume and are forced to "dump" the excess into neighboring countries just to keep their grid stable. Without a plan for storage, Malaysia risks a similar waste of energy.

3) Price Volatility and Negative Rates: The financial impact of this surplus is becoming an everyday reality. Based on an Article by Frederikke Høye (The Danish Dream), as of 16^th September 2025, Denmark has registered a record-breaking 650 hours of negative electricity prices this year, matching the total amount recorded during all of 2024. In these markets, the grid actually pays consumers to take energy off the system because the surplus is a liability. While the graph below by Nord Pool might not show the supply hitting below zero yet, the market price certainly does go close to zero.

Figure 8: Nord Pool 1-Day-Ahead Electricity Prices (Denmark)

For Malaysia, this is a warning. We currently enjoy "flat" pricing due to subsidies, but as we add more solar, TNB will face the same pressure. Eventually, energy will be "worthless" at noon and incredibly expensive at 8 PM.

The Threat to the "Zero Bill"

This is the future problem for Malaysian consumers. As the daytime supply becomes a nuisance for TNB, two things are likely to happen:

1. Your daytime exports might be worth zero credits

2. TNB will have a huge incentive to jack up rates at night when your solar is gone

If this happens and you don't have a way to store your own power, that "Zero Bill" dream will be gone. You'll be giving away energy for free at noon and buying it back at a premium at night.

The Solution: Active Solar (BESS + V2G)

The Malaysian government is increasingly looking toward Battery Energy Storage Systems (BESS) as a solution. By moving toward requirements for buildings with solar installations exceeding 72 kWp to include storage, the policy aims to eventually flatten the curve of energy supply and demand.

While industrial BESS handles the building side, the alternative for Malaysia’s energy future might be parked in our driveways. With Vehicle-to-Grid (V2G) technology, an EV is more than just a way to get around, but it’s a giant mobile battery. Imagine thousands of EVs across the Klang Valley. During the day, they plug in at the office and soak up the surplus solar energy. During the evening peak, these cars can feed a portion of that energy back into the building or the grid. If BESS mandates solve the industrial problem, V2G could solve the residential and city-wide energy imbalance.

We are moving away from Passive Solar (just panels) to Active Solar (Panels + BESS + V2G).  This change is becoming a necessity. The sun may set at 7 PM, but with storage and smart EVs, the solar revolution can power us through the night.

Figure 9: Vehicle-to-Grid replacing Battery Energy Storage Systems (BESS)

Food for thought.

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References:

[1] Residential House in Melaka, COOLTEK, had PV 4.8kWp installed in October 2007, at a total cost of RM125,000 (R26k per kWp) excl. government subsidy.

[2] Vehicle-to-Grid (V2G) explanatory video by the Australian Renewable Energy Agency (ARENA): https://www.youtube.com/watch?v=HFbWC9IWcQ8