Electricity as Commodity

An electricity — the flow of electrons through wires, generated by burning fuel or capturing wind and sun — is a commodity unlike any other: it cannot be stored economically, must be generated at the instant it is consumed, and trades in real-time wholesale markets that settle hourly or sub-hourly. Electricity prices are therefore local (determined by the cost of fuel available in each region), volatile (driven by weather and demand shocks), and increasingly complex (due to renewable generation variability).

The unique commodity

Electricity is fundamentally different from oil, copper, or other commodities. It cannot be stored economically (batteries are expensive and have round-trip losses). It must be generated at the instant it is consumed. It cannot be transported long distances without losses. It trades in real-time markets that settle hourly or sub-hourly.

These properties mean electricity prices are hyperlocal, volatile, and subject to massive swings from small demand or supply shocks. A cold snap increases heating demand and electricity demand; if generation capacity is fully utilized, prices can spike 10–100x normal levels in hours.

Generation sources and dispatch

Electricity generation is dispatched by system operators (grid operators) who match supply to demand in real-time. The dispatching order typically follows:

1. Renewables (wind, solar): Free fuel; dispatched first whenever available.
2. Nuclear: Low marginal cost; typically fully utilized.
3. Coal: Low marginal cost; typically fully utilized; shutting down is costly.
4. Natural gas: Medium marginal cost; dispatched to fill remaining demand.
5. Peaker plants (gas turbines, oil plants): High marginal cost; dispatched only during peak demand.

The marginal generator — the last generator needed to meet demand — sets the price for all electricity. If peak demand requires firing up a $200/MWh natural gas peaker plant, all electricity sells at $200/MWh that hour.

This “pay-as-bid” structure creates the possibility of extreme prices during demand spikes. If a coal plant unexpectedly trips offline during peak demand, prices can spike from $50 to $500/MWh in minutes.

Renewable intermittency and price volatility

The penetration of variable renewable energy (wind, solar) has created new price dynamics. A sunny afternoon floods the grid with solar generation, collapsing prices (sometimes to $0 or negative, as generators pay to offload). A windless evening requires ramping up expensive peaker plants, spiking prices.

California’s electricity market, with 30%+ renewable penetration, experiences more extreme price swings than ever before. Wholesale prices have spiked to $1,000+/MWh during peak evening demand (when solar has dropped and demand is rising).

Wholesale vs. retail markets

Wholesale electricity markets (PJM, CAISO, ERCOT in the US) set hourly prices via auctions. Retail customers (households, businesses) do not directly see these wholesale prices; they see regulated or negotiated retail rates that smooth out wholesale volatility.

In competitive retail markets (like California or Texas), retail prices still track wholesale prices, but with delays and averaging. In regulated utility markets, retail rates are set by regulators based on long-term cost recovery, insulating customers from short-term wholesale price swings.

Regional markets and transmission constraints

Electricity markets are regional because the physics of power flow and transmission limits prevent easy long-distance trading. A shortage in California cannot be easily solved by importing power from Texas because transmission lines have capacity limits and losses.

This creates multiple separate regional markets:

• Eastern US: PJM Interconnection, ISO New England, others
• Midwestern US: MISO Interconnection
• Texas: ERCOT (not interconnected to other US grids; highly isolated)
• Western US: CAISO, others
• Europe: Multiple national markets plus interconnects
• Asia: Mostly not liberalized; prices are regulated

Transmission constraints mean electricity is not truly a global commodity but rather several hundred regional commodities.

Extreme events and market failures

2021 saw the Texas ERCOT grid nearly collapse due to winter storm conditions and inadequate generation capacity. Wholesale prices spiked to the regulatory cap ($9,000/MWh) for hours, costing some industrial customers millions of dollars.

2022 saw the California grid come close to blackouts during heat waves, as air conditioning demand combined with low solar output (evening peak) and gas plant constraints (some offline for maintenance).

These extreme events illustrate the risks of a grid with inadequate capacity margins and high renewable penetration without sufficient storage or backup.

Battery storage and the emerging solution

Lithium-ion battery prices have fallen 90% in the past decade, making grid-scale energy storage increasingly economical. Batteries can charge during hours of surplus generation (solar afternoon) and discharge during peak demand (evening).

Battery deployment is accelerating; California, Australia, and other regions are installing multi-GWh of battery storage. This storage will smooth out renewable intermittency and reduce price volatility.

However, batteries still cost $150–250 per kWh, so multi-day storage (for seasonal balancing) remains prohibitively expensive.

How electricity trades

Most electricity is traded in wholesale auctions run by grid operators:

• Day-ahead market: Generators bid to supply energy for each hour of the next day.
• Real-time market: Final adjustments to meet actual demand, settled every 5–15 minutes.
• Forward market: Contracts for electricity delivery weeks or months in advance.

Retail customers rarely see wholesale prices; they typically buy electricity from utilities or retail providers at fixed or indexed rates.

Risks and system resilience

Electricity systems face several risks:

• Capacity shortfalls: Retiring coal and nuclear plants without sufficient replacement capacity can leave systems vulnerable to peak demand.
• Renewable intermittency: High penetration without storage can cause supply-demand mismatches.
• Cyberattacks: Digitization of the grid creates cyber vulnerability.
• Supply chain constraints: Shortages of transformers, semiconductors, or renewable equipment can limit capacity expansion.
• Geopolitical: Dependence on imports of renewable equipment (solar panels from China, lithium from Chile/Argentina) creates vulnerability.

See also