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A measure of water: enough to cover one acre of land one foot deep. It equals 325,851 gallons.
Adopted means a public body has formally approved it, so it is no longer a draft or a proposal. Binding means the company is required to follow it. Enforceable means a named authority can act if the company does not.
An air permit is a legal document that sets the pollution rules a site must follow. State and local agencies issue most of them. An application or a draft is not a final permit, and an exemption is an agency’s finding that no permit is required.
A backup generator is an engine that makes electricity when grid power is out. A turbine is a machine that spins to make power. A data center can use engines and turbines for its main power as well as for backup.
Also called build-out
A campus is a group of data center buildings on one site. Large sites are built in stages, called phases, and buildout is the full site once every stage is built. Ask which phase a number covers.
Also called closed-loop cooling
Pipes that send the same water around again and again to carry heat away from the computers. The loop still has to pass that heat on. Ask where the heat goes next, because a cooling tower may evaporate water to remove it.
Following the rules in a permit or an approval. A compliance report or an inspection shows whether the rules were followed in a stated period.
How a utility’s costs are divided among groups of customers. An adopted tariff or agreement can assign named costs to one large customer.
Also called A-weighted decibel
A decibel (dB) is the unit for how strong a sound is. The “A-weighted” version, dBA, is adjusted to match how loud a sound seems to the human ear. A small rise in the number means a large rise in noise.
A developer builds the site and an operator runs it. A tenant is a company that rents space there for its own computer equipment. These can be different companies.
Also called renewable energy certificate, REC
A renewable energy certificate (REC) is a record that one megawatt-hour of renewable electricity was made and put on the grid. Whoever owns the certificate can claim that renewable power. Retiring a certificate means using it for a claim, so that nobody else can claim it.
A way to remove heat by letting water evaporate into the air. A cooling tower works this way. The water that evaporates has to be replaced, and the added water is called makeup water.
Also called collateral, credit support
Money or a guarantee that a large customer gives the utility, such as a cash deposit or a letter of credit. It is meant to cover costs if the project is delayed, is dropped, or uses less power than forecast.
Also called interconnection
Generation is making the power, and transmission is moving it long distances on high-voltage lines. Distribution is delivering it to customers. Connection is linking the site to the grid.
The grid is the network of power lines and substations that links power plants to the people who use electricity. A grid region is one part of it. Ask which grid region a clean-power claim covers.
A unit of electricity used over time. One kilowatt-hour is one kilowatt used for one hour. One megawatt-hour is 1,000 kilowatt-hours.
Also called zoning map amendment
A land-use decision is a local government’s final decision that applies its land-use plan or rules. Rezoning changes the zone a piece of land is in, and so the uses allowed there. A decision can be an approval or a denial, and it can later be amended, appealed or reversed.
Also called prominent discrete tone
Low-frequency sound is deep, low-pitched sound, such as a hum. Tonal sound has one pitch that stands out from the sound around it. Ask whether the noise study covers both.
A megawatt (MW) measures power at one moment. A megawatt-hour (MWh) measures energy used over time: a site that runs at 1 MW for one hour uses 1 MWh. Planned capacity is not the same as measured yearly use.
Also called ratepayers
The homes and businesses that pay a utility’s rates, often called ratepayers. If demand falls short of the forecast or a project closes, they may be left with costs.
Also called maximum day demand, MDD
The day when the most water is used. A water system has to be ready for that day, not only an average day.
Also called potential to emit
A permit sets the most pollution a site is allowed to release. That upper limit is not the amount the site did release. Actual amounts come from operating reports.
Also called drinking water
Water that is fit to drink.
Also called power usage effectiveness
PUE compares all the electricity a site uses with the part its computers use. It shows the overhead. It does not show total use, carbon emissions or how much useful computing was done.
Also called reclaimed wastewater, recycled water
Treated wastewater that is used again, for example for cooling or for watering land.
Renewable sources, such as sun and wind, restore themselves in a short time. Carbon-free sources make electricity without giving off carbon dioxide. Nuclear power gives off no greenhouse gases while making power but is not renewable, so ask which sources a claim counts.
Also called water replenishment
Replenishment means returning water to the area around a site, and “water positive” is a claim to replenish water. Such a claim needs its own method, place, timing and proof of the benefits delivered. By itself, it does not show that the local supply can meet the site’s demand.
A utility tariff sets the rates and the terms of service. Stranded costs are costs that still have to be paid for when infrastructure is no longer needed as expected. Contracts can say who carries that risk, with exceptions that are worth reading.
Also called public service commission, public utility commission
A utility commission is the public body that regulates utility rates, and an order is its written decision. A docket is its file of all the documents in one case. A rate case is the process that sets what a utility may charge.
Also called public water supplier
The water utility is the public body or company that supplies water to a town. A capacity study is its review of how much water it can supply.
Also called consumptive use
Withdrawal is water taken from a source. Consumption is the part that leaves the local water environment, for example when it evaporates. Water that is returned somewhere else may still affect the local supply.
The area of land that drains to one stream, river or lake.
Also called water usage effectiveness
WUE compares the water a site uses with the electricity its computers use, often in liters per kWh. Check what the figure covers and for what time period. Ask for the total amount of water too.
Also called annual matching, 24/7 matching
Yearly matching, often called annual matching, balances the power made and the power used over a whole year. Hourly matching compares them hour by hour. Ask which grid region, which energy sources and what percentage are covered.