An exhaust aftertreatment system may include a reductant tank, a reactor system, a storage tank, a first conduit and a second conduit. The reactor system may receive reductant from the reductant tank and may output a gas comprising ammonia. The storage tank may receive gas comprising ammonia from the reactor system and may store a volume of gas comprising ammonia. The first conduit may communicate gas comprising ammonia from the reactor system to a stream of exhaust gas. The first conduit may bypass the storage tank. The second conduit may communicate gas comprising ammonia from the storage tank to the stream of exhaust gas.